Odometer running unusal 89 328GTS

My 81 308's odometer crawls when the sar is stoped an not moving with the
engine running. The lst time I drove it when goinig over a seam in the road (just enough to unsettle the car at speed but not a jolt, the speedometer dropped from 70 to 40 then back to 70, the tack did not falter.
Differnt but in the same area.

Maybe somebody has an idea that will help us both.

stephen

 

Start with replacing the speedometer sender, it is screwed into the top of the transaxle...has a wire pigtail sticking out of it. Unplug is from the pigtail, should at least stop the miles accumulating, until you get a new one. Daniel at Ricambi has them in stock.

Dave

 

So did that fix the problem or have you not driven it to check yet?

Jeff

 

Is this sensor responsible for both speedo and odo?

 

We've used this shop for over 15 years; they do good work, fair prices, fast "turn-a-round," too. Yeah they don't have a "website," but clocks, Speedo’s tachs is what their about. 10 years ago I sent them a tachometer out of a 1937 Bugatti, and they repaired it quickly as if it came out of a Buick! Very cool the way the shaft of the Bugatti extends into the cabin left of the "Steering Wheel," (right hand drive) and at the top is a Lucas Magneto, but inside the engine compartment is a belt made of leather attached to the tach with an "idler pulley," for tension (after you "crank start it up!).

As for your car; if the odometer is functional there's a gear internally that's not! These guys do good work, and can (if you really care how fast you’re going) request it be "Federally Certified!" Show that to the next "Highway Patrolman you meet!" If you get a speeding ticket, and the officer fails to bring his certification (caught by shadowing you), or forgot his certification of the GUN, and his "accreditation up to date," on how to use it, you walk! But you must ask for these documents as the State doesn't have to help you get out of a ticket. Ignorance of the Law is no excuse... (I may get that as a tattoo some day). Hope this helps you as they have us!

Later,
Hank

Speedometer & Clock Company. 2337 S Michigan Ave. Chicago, IL 60616 (312) 842-6378.
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The sensor operates both the speedometer and the odometer. The circuit can fail such that either one stops working properly.
The symptom described above is one indicating significant electrical noise in the 12V circuit somewhere. This usually comes from the alternator going bad. In my original design for a replacment board for the speedometer my 12V input filtering was not adequate, giving those same symptoms, esp. when cranking the engine.
I would start by checking connections such as the engine ground and the other beautifully hidden and disguised grounds throughout the car

And thanks for reminding me how much I miss my 1969 1750GTV! Owned it for the fisrt 10 years of its life, what a blast to drive

Gerrit

 

Wow, you waited 9 months to correct the problem? Did you just drive it with the sendor disconnected?

 

I have a similar problem. The odometer is fine (and only works when the car is moving) but the speedo needle shows something like 20mph when I could be doing 50mph. Is this the impulse generator problem and does anyone know the part number please? Its a 1987 UK spec 3.2.
Many thanks.
Peter

 

Yet another thread showing not to trust the odometer reading.......too easy to disconnect or drive not connected.....fixed but not fixed, old thread. Cool GTV, though, my other dream car......